1. Field of the Invention
The present invention relates to a drum cutter-loader longwall mining machine, in general, and to a drum cutter-loader longwall mining machine equipped with a rotatable auxiliary debris crushing drum, in particular.
2. Description of the Prior Art
Japanese Published Patent Specification No. 53-76 902 discloses a coal-crushing device for a mining machine which includes a crushing roll rotatably supported at a first end of a support arm which is mounted to an end of the mining machine body and above a longwall conveyor. The second end of the support arm carries a driving motor and is pivotally connected to the machine body. The crushing roll is driven by the driving motor via gearing which is on the inside of the support arm. The axis of the driving motor, which serves only for driving the crushing roll, lies coaxially with the swivelling or pivoting axis of the crushing roll support arm. This same axis is also coaxial with the pivot axis of the cutting drum support arm, which besides a cutting drum also carries a separate motor and gearing for driving the cutting drum.
German patent application No. P 37 36 609.2 describes a similar cutter-loader machine used in the mining of thick seams which is also equipped with an auxiliary drum to crush mined debris. The machine includes cutting drums situated at both ends of the machine body which are retained by separate height-adjustable and pivotally-mounted support arms. Each of the cutting drums is driven by a separate drive motor mounted on the goaf side of each of the respective support arms. The auxiliary crushing drum, which is fixed to the front of the machine body, is connected by gearing to one of the driving motors. In one embodiment, the auxiliary drum is rotatably supported by a shoulder of the support arm which spans the support arm pivot axis. In a second embodiment, the auxiliary drum is rotatably supported by a jib which is rigidly fastened to the rear end of the protective housing which encloses the driving motor of the cutting drum. In either embodiment, however, the auxiliary drum is caused to be raised and/or lowered through the pivoting action of the support arm to which the auxiliary drum is directly or indirectly integrally secured. The auxiliary drum does not pivot independently of its associated support arm.
Modern cutter-loaders, on account of their great power requirements, must be provided with powerful driving motors which have correspondingly large physical dimensions. Since the motors considerably influence the overall dimensions of the machine body, they are frequently arranged outside the machine body on the support arms of the cutter-loader, above the longwall conveyor means. This particular motor mounting arrangement results in an advantageous lowering in the overall height of the machine body while avoiding an undesirable reduction of the machine gate space caused by encroachment of the driving motor housing into the gate space. The machine gate space being that space of the machine body through which mined debris carried on the conveyor may pass. However, such a construction prohibits the driving motor from being fixed coaxially with the pivot axis of the support arm. In such "low height" devices, the installation of a second drive motor for driving the auxiliary drum is required and can only be achieved on those machines having very long support arms for the cutting drum and the auxiliary drum. Support arms of such dimensions not only considerably increase the overall length of the cutter-loader, but also increase the manufacturing costs and thus the price which has to be paid for such machines.
Occasionally it is desired to supply the auxiliary drum with driving power corresponding to the full driving power of the cutting drum, which has proved to be especially advantageous in maintaining continuous underground mining operations. When such high power is desired, the only course of action, for reasons of space, is to connect the driving motor of the cutting drum to the auxiliary drum by gearing. Only through direct connection with such a power supply is it ensured that the auxiliary drum will operate continuously and unblocked thus avoiding interruption of the mining operation where debris suddenly occurs on the conveyer.
The cutter-loader disclosed in previously mentioned German patent application No. P 37 36 609.2 provides for the driving of the auxiliary drum with the driving motor of the cutting drum. The auxiliary drum is rotatably supported by a jib which is rigidly connected to the driving motor. The driving motor is secured to the support arm and its driving axis is arranged outside or offset from the support arm pivot axis. The geared communication between the auxiliary drum and the driving motor is effected by a gear train situated either in the jib or in a shoulder of the support arm. Since the axis of the driving motor lies outside the support arm pivot axis and the auxiliary drum is rigidly connected to the driving motor via the jib, the auxiliary drum is essentially integrally connected with the support arm and participates in the pivoting movement thereof. Therefore, the height position of the auxiliary drum is dependent on, and controlled by, the height position of the cutting drum support arm.
Such unwanted variations in the position of the auxiliary drum can be eliminated by a pivotable mounting of the auxiliary drum jib on the free front end of the driving motor with the aid of an elaborate servo drive mechanism, as German Pat. No. 35 27 253 shows. However, inclusion of such a mechanism increases the construction and maintenance costs of the machine. Still further, the addition of such a servo drive mechanism for independently controlling the height of the auxiliary drum does not solve the problem of conserving the overall length of the machine, since, as German Pat. No. 35 27 253 illustrates, the jib pivot axis is disposed offset and forwardly of the support arm pivot axis as a result of the space which must be provided in order to account for the structural elements of the servo mechanism.
It is therefore an object of the invention to provide a longwall mining machine of the type having a cutting drum and an auxiliary crushing drum associated therewith which are driven through a positive geared communication with cutting drum driving motor.
It is a further object of the invention to provide a longwall mining machine of the type having a cutting drum and an auxiliary crushing drum associated therewith in which the support arm of the cutting drum and the jib of the auxiliary drum are independently adjustable in height.
It is a further object of the invention to provide a longwall mining machine of the type having a cutting drum and an auxiliary crushing drum associated therewith in which the support arm of the cutting drum and the jib of the auxiliary drum are pivotable about the same pivot axis.
It is a still further object of the invention to provide a longwall mining machine of the type having a cutting drum and an auxiliary crushing drum associated therewith which is compact in size and relatively simple to construct and maintain.
Still other objects and advantages will become apparent when one considers the attached drawings and the description of the invention presented hereinbelow.